In Search of the Best Sour Fish (Pla Som)

Kasma Loha-unchit, July 23rd, 2011

Pla som, or sour fish, is one of my very favorite foods from the northeastern Isan region, which is also known for its sour sausages. It’s made in a similar way as the Isan sour sausages, using fermented rice as the souring agent. I’m partial to fish and a perfectly fermented and crispy-fried sour fish is so delicious it’s hard to stop eating it! The problem is: perfection is hard to find, even in its home territory.

Ready-to-eat sour food

My first encounter with pla som was some fifteen years ago in the then small riverside town of Nakhon Phanom in the northeastern corner of Isan. It was at a small rice shop near the hotel I spent the night. Hungry and looking for a good place for breakfast, I walked down one of the streets and noticed a busy rice shop crowded with customers – a good sign! Among the assortment of ready-made dishes in front of the shop was a yummy-looking fried fish topped with crispy fried garlic, fried dried chillies, sliced shallots and cut Thai chillies. I soon discovered it wasn’t any ordinary fried fish. It had a very unusual and delicious sour flavor definitely not from lime juice, tamarind, vinegar or any other sour condiment. That introduction to pla som was truly memorable and I fell deeply in love with this Isan food.

(Click images to see larger version.)

In those days, Isan food hadn’t yet become popular in the main heartland of the country’s central region. It was impossible to find it in any eatery or restaurant in the capital, even in the few so-called Isan restaurants just opening in the city. But memories of that first encounter remained vivid in my mind and on my tongue. I could only dream of another trip to Isan to savor the delicacy.

Sour fish at Si Saket

Fast forward half a dozen years. Michael and I took a trip to Isan with our friend and adopted brother Sun, who drives for my Thailand tours. I was showing Michael around to the places I’d been and we were exploring new places as possibilities for organizing a future tour. I hadn’t offered an Isan trip for years as traveling in the vast Isan region, Thailand’s largest, during the last two decades of the last century could be tedious and standard tourist accommodations lacking in many of the fascinating areas worth visiting. With Isan now a popular destination among domestic Thai tourists and Isan food becoming an “in” cuisine nationwide, it was a perfect opportunity to check out the new infrastructure, as well as the lively markets and local eateries I’d been reading about in Thai travel magazines.

Sour fish dish in Surin

We had just arrived in Nong Khai on the Mekong River. It was late in the day and after checking into a family-run guest house near the river, we went for a walk along the alley by the waterfront, hoping to find a good restaurant with views of the river for dinner. My eye caught a signboard with the words pla som and immediately I insisted that we have dinner there.

I ordered the pla som while Michael and Sun chose a couple of other dishes. Soon, both of them understood why I was so excited about eating there. The fish was very quickly gone before the other dishes received our attention. The next evening, after a full day of exploration, Sun was the one to adamantly insist that we return to the same place for dinner and, this time, forget about other dishes and just order three plates of pla som, one for the each of us!

Sour fish in Ubon market

For the rest of that trip, as we journeyed along the Mekong east- and southward to the border province of Ubon and then cut westward to Surin and Buriram before heading back to Bangkok, we kept an eye out for pla som but, unfortunately, did not find any place with as good a pla som as we had in Nong Khai. Some were actually rather disappointing. Most of the pla som we saw were uncooked, sold in open tubs in the fresh marketplaces and made with whole fish, as it’s traditionally done, particularly small silver barbs (pla tapian) that do have a lot of small bones. The pla som we had in Nong Khai was made with chunks of a large fish with plenty of moist meat and very little bones.

Sour fish in bulk at Don Wai

Michael and I love to visit open-air fresh markets in Thailand and Sun often drives us to marketplaces far and near. We soon begin to notice raw pla som being sold in some of the larger gourmet fresh markets in or near Bangkok, like Aw Taw Kaw (Or Tor Kor) and Don Wai, either already packaged in plastic bags or sold bulk in big piles. The pla som made by Kamnan Jun sold in Don Wai market is particularly good. It’s made with a fish called pla nuanchan in large mostly filleted chunks with skin still on. The skin is important as it adds a good texture to the fish when it is crispy-fried.

The first time I saw pla som at Don Wai, I bought two large bags and fried all the pieces up the next morning for breakfast. Sun, whose home is in Nakhon Si Thammarat in the south, planned to breakfast with us before making his long drive home. He was so delighted to have so many pieces of pla som to feast on. The fish was crispier and even more delicious than he remembered having in Nong Khai. He was convinced that I must have a secret way of frying the fish that enhanced the crispiness and flavor. He devoured with great pleasure as much as he could but there were so many pieces we couldn’t possibly finish the two big plates. So he decided he would wait till afternoon to begin his long drive, so that he could have lunch and finish off the rest!

Don Wai sour fish vendor

Sour fish at Don Wai

Vientiane Kitchen's fried sour fish

Pla som has become much better known among Thais all over the country as Isan food continues to soar in popularity the past decade. As migrant workers from Isan find their way around the country, I’m seeing raw, ready-for-cooking pla som in markets far and wide, even in the southern region. A number of Isan restaurants in Bangkok now have it on their menus but so far nothing near as good as the best pla som I’ve had in Isan or that I’ve fried myself from fish bought at Don Wai and Aw Taw Kaw. Vientiane Kitchen on Sukhumvit 36 serves an acceptable one after the restaurant remodeled recently and put in a new menu (and perhaps new cooks, too), but it lacks the crispiness that has become a trademark of delicious fried pla som.

I can even find ready-to-cook pla som in my local Cambodian market in Oakland (see my blog on Sontepheap Market), in packages in the freezer imported from Thailand and labeled in Thai as pla som Mae Jinda. The ingredients are shown in English though, listing fish, garlic, rice and salt. To preserve the fish better for its long journey here, it is made saltier than what’s available in Bangkok’s markets and needs to be eaten with plenty of rice. Delicious though it is!

"Mae Jinda" sour fish at Sontepheap

Sour fish out of package

Very fresh tilapia for making sour fish

I’ve also taken to making my own pla som and teach it in one of my advanced classes. (See Menus for Advanced Set F.) Definitely a fish with skin still on makes the best pla som. I’ve tried making it with red snapper, catfish, basa (swai) and tilapia. The best result so far is with very fresh tilapia that I buy live from the tanks in Asian fish markets, that I then fillet to remove only the center skeleton, head and tail, but leaving the skin on. In the Bay Area it takes about a week to sour the fish. Rubbed with a coating of tapioca flour before frying, it delivers a most satisfying combination of crispiness and natural sour flavor to rival the best I’ve had in Isan’s restaurants.

Preparing the tilapia

Week-old soured tilapia

Sour fish at Bao Pradit, Mukdahan

My most recent trip to Isan was in December 2009 with a group of twelve on a special northeastern Thailand tour. (On Picasa, see Kasma’s Northeastern Trip Photos, Part 2.) Whenever and wherever I saw pla som on a menu, I would order it. Several in my group loved it, but like me, they soon discovered that quality and taste could vary substantially. By far the best we had was at a truly native Isan restaurant in Mukdahan, called Bao Pradit. It’s south of town along the river, serving really hardcore Isan food made with local ingredients not found in other regions. With all the wonderful choices and fiery hot range of flavor combinations, Sun asked that I order for him his own plate of pla som and that’s the only thing he ate that night with a heavenly grin on his face. I would have to say it really was the best of the best pla som I’d ever had.

This fall, I’m offering another special 21-day trip to Isan and I’m already dreaming about a fabulous dinner in Mukdahan!”